Striving for longevity is popular these days. Not the type that keeps the elderly alive despite advanced decline, but the type that staves off infirmity for as long as possible. The popular movement’s epicentre is probably Los Angeles, where tech entrepreneur Bryan Johnson lives. He spends $2 million a year on diet, exercise, sleep, supplements and extreme efforts such as gene editing. He’s currently ageing at the pace of two-thirds of a year for every chronological year.
But Dunedin is an epicentre of ageing science. Johnson and other longevity influencers measure their ageing rate using a test developed from the Dunedin Study, whose 1000+ participants are celebrating their 52nd birthdays about now. It’s licensed to a US-based commercial lab, TruDiagnostic, which sells it as a pinprick blood test kit.
The test works by measuring so-called “epigenetic” changes to DNA. These changes happen on top of our DNA, without changing its underlying arrangement. This happens in response to the passage of years but also lifestyle and life events. The changes involve molecules called methyl groups attaching to DNA, which alters how genes are expressed. Measures of them that gauge ageing are known as methylation clocks or epigenetic clocks.
Over the two decades the Dunedin Study members’ ageing rate has been assessed, one person aged 0.4 years per chronological year and the fastest ager accrued 2.44 biological years per year. This personal rate of ageing for each study member was calculated by measuring biomarkers of cardiovascular, metabolic, kidney, liver, lung, immune and dental health biomarkers.
Scientists at Duke University, North Carolina, looked also at each member’s epigenetic changes. Other scientists used machine learning to discover areas of epigenetic change that reliably correlate with the known ageing rate. These areas are scrutinised on cells from the blood test. Thus DunedinPACE (Pace of Ageing Calculated from the Epigenome) was born.
The goal of these interventions is to help more people evade the onset of ill health and frailty for longer.
One of the inventors of DunedinPACE is Daniel Belsky, an associate professor at Columbia University, New York, who specialises in the molecular epidemiology of ageing. He was the lead author of a paper that reported how DunedinPACE successfully predicted illness, disability and death when used in some of the world’s other great longitudinal studies, such as the Framingham Heart Study.
He says DunedinPACE is considered to be among the best available ageing biomarkers. “It’s unique in being the only ‘speedometer’ biomarker – a single time-point measurement of the rate of ageing-related health decline.”
He and colleagues used it to analyse the epigenomes of people in the Calerie trial, in which participants restricted their caloric intake by about 12% for two years. The trial produced extensive data supporting a positive impact on health and ageing biology in the calorie-restricted group, yet other epigenetic clocks failed to detect a difference. “DunedinPACE was the only clock sensitive to the effects of intervention,” says Belsky.
DunedinPACE was designed to measure the effectiveness of interventions that cultivate healthy ageing. “The goal of these interventions is to help more people evade the onset of ill health and frailty for longer,” says Belsky.
Back in Los Angeles, DunedinPACE is the timer of choice for the Rejuvenation Olympics. Johnson, who’s 47, runs the competition and is fifth. He moved up the chart when he made rule changes, including that the score was no longer age-adjusted.
That adjustment seemed fair because as we get chronologically older, ageing accelerates. One analysis in Belsky’s paper showed that on average, 30-year-olds age about 20% slower than 45-year-olds, and near-centenarians age 10-20% faster. Men aged faster in their golden years than women. And in the Olympics, fractions make a difference.
